1. Field of the Invention
The present invention relates to a recording apparatus and a dubbing system including the same, and more particularly to a dubbing system for copying for example image and/or sound recorded on a recording medium onto another recording medium.
2. Related Background Art
In a conventional dubbing system, an original recording medium is loaded in a master unit composed of a reproduction apparatus while an unrecorded recording medium is loaded in a slave unit composed of a recording apparatus, and the dubbing operation is achieved by starting the recording operation in the slave unit simultaneously with the reproducing operation in the master unit.
In such a conventional structure, synchronization of the start of reproduction in the master unit with that of recording in the slave unit is to be done by the operator, and, in the conventional apparatus, the reproduction and recording have been started manually. More specifically, the dubbing operation is started after the selection of a track to be reproduced and a track for recording. However, in a system capable of recording image and sound in a mixed manner and capable of recording various information in various modes, the operating mode of the slave unit has to be changed according to the recording mode of the original medium. Consequently the conventional system has required extremely complex operations for the synchronized operation of the master and slave units. Thus the dubbing is started and stopped while monitoring the reproduced image or sound, so that the recording is often interrupted during operation or terminated by error. Also, in a case of reproducing an image and related data, there are required operations of confirming the data by reproduction on the slave unit, and dubbing the image by entering said data in the master unit, and the operation becomes very cumbersome as such operation is to be conducted for each track.
Also, as an example of such a system, there is already known a so-called still video system.
The recording unit of such a still video system records the image signal of a field on each of concentric tracks formed on a magnetic disk. The image signal is recorded either in a mode of recording an image signal of a field on a track (hereinafter called a field recording mode), or in a mode of recording the image signal of an odd field and an even field on two tracks thereby representing the image signal of a frame by the signal of two fields recorded on two tracks (hereinafter called a frame recording mode), and at the same time there is recorded an index (ID) signal indicating whether the image signal is recorded either in the field recording mode or in the frame recording mode.
During reproduction, the signal recorded on a desired track is reproduced by tracing said track with a magnetic head, then the ID signal is separated from the reproduced signal, and it is discriminated whether the separated ID signal indicates the frame recording mode or the field recording mode. If the image signal reproduced together with said ID signal from the desired track is identified as that of the frame recording mode, the reproduction is made in a mode in which the image signal of a frame is reproduced by alternately reproducing the desired track and a neighboring track in respective field periods (hereinafter called a frame reproducing mode). On the other hand, if the image signal reproduced together with the ID signal from said desired track is identified as that of the field recording mode, the reproduction is conducted by repeatedly reproducing said desired track and generating the image signal of a frame by forming an interpolated signal and a non-interpolated signal alternately in respective field periods from the thus reproduced signal, and delaying the interpolated signal by a half of the horizontal scanning period (1/2 H) for skew compensation (hereinafter called a field reproducing mode).
There is also known a so-called dubbing system in which the image signal reproduced from the magnetic disk in a reproducing unit is sent to another recording unit for copying on another magnetic disk.
FIG. 12 schematically shows the structure of a reproducing unit in a conventional dubbing system.
In FIG. 12, a magnetic disk 201 is rotated at a predetermined revolution by a motor 202, and magnetic heads 203a, 203b are moved by an unrepresented head moving mechanism, in response to an instruction from an operation unit, to desired tracks for reproduction, selected from plural concentric tracks formed on said magnetic disk 201. Signals recorded on said tracks are reproduced by the magnetic heads 203a, 203b, amplified by preamplifiers 204, 205 and respectively supplied to terminals a and b.
In response to an instruction from a system controller 219, a switch 206 is connected by a switch controller 218 to the terminal a during the initial operation, whereby the output of the pre-amplifier 204 is supplied to an ID signal demodulating circuit 209.
Said ID signal demodulating circuit 209 separates and demodulates the ID signal from the signal supplied from the pre-amplifier 204 through the switch 206, thereby reproducing, for supply to the system controller 219, ID data containg field/frame discrimination data indicating whether a signal reproduced by the head 203a is recorded in the field recording mode or in the frame recording mode.
The system controller 219 discriminates whether the field/frame discrimination data in the ID data supplied from the demodulating circuit 209 indicate either the field recording mode or the frame recording mode, and, in the case of the former, sends an instruction to the switch controller 218 for controlling the switch 206 according to the frame reproducing mode.
The switch controller 218 receives pulses corresponding to the frequency of rotation of the magnetic disk 201 from a pulse generation (PG) detecting circuit 217, and, in response to the instruction for the frame reproducing mode from the system controller 221, connects the switch 206 alternately to the terminals a and b at each revolution of the magnetic disk 201 in synchronization with said pulses.
In an unrepresented core of the magnetic disk 201, a magnetic member is provided for indicating the rotation period of said disk 201. A pulse generating (PG) coil 216 detects said magnetic member in each revolution of the magnetic disk 201 and generates a pulse, which is subjected to wave form shaping in the PG detecting circuit 217 and supplied to the switch controller 218 as a PG pulse representing the rotating period of the magnetic disk 201.
If the field/frame discrimination data in the ID data from the demodulating circuit 209 indicate the field recording mode, an instruction is sent to the switch controller 218 for controlling the switch 206 according to the field reproducing mode.
In this case the switch controller 218 continuously connects the switch 206 to the terminal a.
The signal released from the switch 206 is supplied to a luminance signal FM demodulating circuit 207 and a color difference signal FM demodulating circuit 208. The luminance signal demodulating circuit 207 extracts an FM luminance signal component from the signal supplied from the switch 206, demodulates said component and sends the demodulated signal to a luminance signal process circuit 210. Also, the color difference signal demodulating circuit 208 extracts an FM color difference line-sequential signal component from the signal supplied from the switch 206, then effects demodulation and sends the demodulated signal to a color difference signal process circuit 211.
Said process circuits 210, 211 effect different processes in the field reproducing mode and in the frame reproducing mode, according to the instruction from the system controller 219.
In the field reproducing mode, the luminance signal process circuit 210 effects de-emphasis on the demodulated luminance signal, then effects interpolation and skew compensation, and sends the obtained luminance signal Y to a composite video signal forming circuit 212. Also, the color difference signal process circuit 211 effects de-emphasis and interpolation on the de-modulated color difference line-sequential signal, then effects a synchronizing process and further applies skew compensation to obtain two color difference signals R-Y, B-Y which are supplied to the composite video signal forming circuit 212.
In the frame reproducing mode, the luminance signal process circuit effects the de-emphasis on the demodulated signal but does not effect the interpolation and skew compensation, and sends the obtained signal, as the luminance signal Y, to the composite video signal forming circuit 212. The color difference signal process circuit 211 effects de-emphasis and synchronization on the demodulated line-sequential color difference signal without interpolation and skew compensation, and the obtained two signals are supplied, as the color difference signals R-Y, B-Y, to the composite video signal forming circuit 212.
The composite video signal forming circuit 212 utilizes the luminance signal Y from the process circuit 210 and the two color difference signals R-Y, B-Y from the process circuit 211 for forming a composite video signal, based for example on the NTSC system, which is released from an output terminal 213.
The reproducing apparatus shown in FIG. 12 is provided with dubbing output terminals 214, 215 which respectively release the output signals of the demodulating circuits 207, 208 for supply to other equipment.
The dubbing of the image signal recorded on the magnetic disk 201 onto another magnetic disk is conducted through said output terminals 214, 215. Different from the signals from the process circuits 210, 211, the signals released from the dubbing output terminals 214, 215 in the field reproducing mode are not subjected to interpolation and skew compensation, and are therefore free from the deterioration caused by said process circuits 210, 211. Also, since the luminance signal component and the line-sequential color difference signal component are supplied in separate states, the processes of mixing and separation of said components can be dispensed with in comparison with the case of dubbing in the state of a composite signal. Thus, there can be prevented signal deterioration resulting from said processes, and the signal reproduced from the disk 201 can be dubbed onto another magnetic disk without deterioration.
However, in a case of a dubbing operation utilizing the above-mentioned dubbing output terminals, if the reproducing unit reproduces the signal in the field reproducing mode while the recording unit records the signal in the frame recording mode, the image signal of a field is recorded on two adjacent tracks of the latter disk, with an ID signal indicating the frame recording mode. If the image signal of said disk is reproduced according to the ID signal recorded therein, the signals recorded on two tracks are merely reproduced alternately without interpolation or skew compensation with aberrated synchronization signals, since the ID signal indicates the frame recording mode. Such output signals cannot provide a proper image on the monitor.